Landmine with pressure trigger

ABSTRACT

A landmine having a plunger operative, when moved, to release a firing pin to thereby set off an explosive charge. The firing pin is held by a flyweight that is yieldably mounted to the plunger so that when the plunger is momentarily moved at a relatively rapid speed the inertial resistance to movement of the flyweight will inhibit the movement of the flyweight, thereby preventing the release of the firing pin.

United States Patent Jany 51 July 24, 1973 LANDMINE WITH PRESSURETRIGGER 2,453,715 11/1948 Liluegren et all 102/8 3,205,817 9/1965Madlener et all.... 102/8 [75] 30mm" Volkmghause 3 450 049 6/1969 Dare102/80 Frondenberg(Ruhr), Germany [73] Assignee: Bauia-Werke RichardRinker,

Mendel, Germany Przmary Examiner-Samuel W. Engle Attorney-George H.Spencer et a]. [22] Filed: Aug. 26, 1971 [21] Appl.No.: 175,205

[57] ABSTRACT [30] Foreign Application Priority Data Oct. 9, 1970Germany P 20 49 656.4 A landmine having a plunger operative, when moved,to release a firing pin to thereby :set off an explosive [52] U.S. Cl.102/8, 102/70 charge. The firing pin is held by a flyweight that is [51]Int. Cl F42b 23/00 yieldably mounted to the plunger so that when the[58] Field of Search 102/8, 70, 78, 80, plunger is momentarily moved ata relatively rapid 76 speed the inertial resistance to movement of theflyweight will inhibit the rnovemekoi the flyweight, [56] ReferencesCited thereby preventing the release of the firing pin.

UNITED STATES PATENTS 1,682,560 8/1928 Gruber 102/8 11 Claims, 5 DrawingFigures 5 36 :0 36? 1*" 1 7 o, 1 2 2 3 1 1 o 5 j n r 1/ Vfi ,r 47 7:3 313. 1 j

1 4 V WW /i a 25 e 7 21 1 34 39 3 f MM z 22 3., 4,! i z i3 7 g 8 9 5 4o41 mimgomz I s. 147. 526

SM 2 BF 2 LANDMINE WITI-I PRESSURE TRIGGER BACKGROUND OF THE INVENTIONThis invention relates to a landmine with a pressure trigger comprisinga pressure plate that is supported by a heightwise displaceable plungerand can be depressed against spring pressure, the plunger in thedepressed state releasing a srping biased firing pin.

SUMMARY OF THE INVENTION It is the object of the invention to providesuch a landmine that is so constructed that it can be dropped, forlaying a mine barrier, from a relatively high height without there beinga danger of accidentally detonating the landmine if it should landbottom-down with the pressure plate hitting the ground. This object isaccomplished by providing a flyweight that is mounted for heightwisemovement with respect to the plunger. A spring element yieldably urgesthe flyweight downwardly of the plunger and the firing pin is caused tobear against the flyweight. With this construction, when the plunger isforced downwardly at a relatively slow speed, as when a truck runs overthe landmine, the flyweight moves downwardly with the plunger to releasethe firing pin. However, when the plunger is caused to move momentarilyat a relatively high speed, as when it is dropped from a truck or anairplane or helicopter, the inertial resistance to movement of theflyweight will prevent movement of the flyweight so that the firing pinis not released.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view ofthe landmine.

FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1.

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 1.

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 1.

FIG. 5 is a view of the landmine to a reduced scale taken along the line5-5 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The landmine is designed for atriggering pressure of about 300 kg and comprises-a housing 1 made ofasynthetic material. The housing 1 has a downwardly facing opening thatis closed by a bottom 2. A tubular guide 3 is formed in the middle ofthe housing 1. A plunger 4 is disposed in an opening in the guide 3. Theplunger 4, which is also made of 'a synthetic material, is pressedupwardly by a compression spring 5 to a position wherein a collar 6 atthe bottom of the plunger abuts a shoulder 7 formed in the lower portionof the guide 3.

The lower end of the compression spring 5 bears against a cup-shapedscrew 8 that is threaded into the guide 3. The force appplied by thecompression spring 5 against the plunger collar 6 can be adjusted bychanging the extent to which the screw 8 is threaded into the guide 3. Atubular spacer 9, supported by and located in the interior of the screw8, is disposed in alignment with the plunger collar 6.

A pressure plate 10 is supported to rest on the plunger 4 and is tightlysecured to the housing 1 by the fastening member 11 held in place bytensioning bands 12.

A plurality of pins 13, such as five, are evenly distributed along theperiphery of the pressure plate 10. Each pin 13 extends inwardly of thepressure plate and enters a recess 14 of the housing 1. A screw 15 isthreaded into each pin 13, the heads of the screws being supported, viawashers, at the interior of the housing 1. A compression spring 16 isdisposed in each recess 14 and extends between the housing 1 and thepressure plate 10.

An axially displaceable firing pin 17 is disposed trans verse to theplunger 4. The front end portion of the pin 17 has a tip extending intothe plunger guide 3 through a bore 18. The firing pin 17 is under springtension from a compression spring 19. The end of the firing pin remotefrom the tip is provided with a constricted neck 20 that is in alignmentwith a blocking latch 21 of a timer 23 that is fastened in a housingchamber 22.

The timer 23 is mounted in a ring 24 which is fastened to the housing 1by two screws 25. The timer 23 is installed in a tensioned state and itsspring mechanism (not shown) is released by a. rotation of of arotatably mounted handle 26.

An initial triggering device 27 and a primer charge 28 are disposed inalignment with the firing pin 17. An explosive charge 28' is locatedadjacent the primer charge 28.

The side of the plunger 4 that faces the firing pin 17 has a recess 29in which a flyweight 30 is mounted for heightwise movement with respectto the plunger in the same direction as the movement of the plunger 4 inguide 3. The flyweight is made of a relatively heavy high densitymaterial such as non-rusting steel. The maximum stroke of the flyweight30 with respect to the guide 3 is the same as that of the plunger 4 inthe guide 3, the lower limit of this stroke being determined by thespacer 9 and the upper limit of this stroke being determined by theshoulder 7. This stroke should, preferably, be no more than 2.5 mm. Inaddition, the flyweight 30 is yieldably urged downwardly by acompression spring 31 to a limit stop 32 formed by the top of the collar6. The downward force applied by the spring 31 is less than the upwardforce exerted by the spring 5. A bore 33, having a greatercross-sectional area than the largest crosssectional area of the firingpin 17, is located in the. flyweight 30 in alignment with the firingpin. A firing lip 34, formed on the flyweight 30, extends upwardly fromthe bottom wall of the bore 33 and bears against the front of the firingpin 17. A bore 35, located in the plunger 4, is in alignment with thebore 33. The bore 35 has a cross-sectional area at least equal to thatof the bore 33. The end portion of the initial triggering device 27which faces the firing pin 17 is located within the bore 35.

A resilient ring 36, which may be of rubber, is fastened to the housing1 and extends above the top of the pressure plate 10. The pressurerequired to compress the ring 36 is less than the pressure required totrigger the landmine. When a vehicle drives over the landmine and exertsa pressure that exceeds the predetermined triggering pressure, the ring36 is compressed to such an extent as to cause the pressure plate 10 toforce the plunger 4, together with the flyweight 30, downwardly againstthe force of the spring 5 until the lip 34 releases the firing pin 17.The firing pin is: thus released to be moved by the spring 19 againstthe initial triggering device 27 to thus detonate the landmine. Theamount of this movement of the pressure plate by the plunger 4 is lessthan 2.5 mm.

If the landmine is to be dropped from a moving vehicle to make a minefield, the handle 26 is first moved from its safe position by about 90to its armed po sition. This causes a lever 38 and a pin 37 on the timer23, which were blocked by a pin 38a in the handle 26, to be released sothat the biased timer can run down in a preselected time period, e.g., 1to 2 minutes, and then pivot the blocking latch 21 out of the neck ofthe firing pin 17 via a gear drive 39. Before this time has expired, thespring tensioned firing pin 17 is thus safely held so that it cannot hitthe initial triggering device 27 even when the landmine hits the ground.

To secure the handle 26 in the safe position, two spring tensioned pinsare so located on the ring 24 that in the safe position they releasablyengage detents 41 located in the handle 26.

If the landmine is to be picked up again, as for subsequent use, thehandle 26 is moved from its armed position to its safe position so thatthe blocking latch 21 is pivoted back into the neck 20 of the firing pin17 and so that the spring tensioned pins 40 again engage the detents 41.

A danger exits that a landmine may fall accidentally from a truck orhelicopter to the ground with its pressure plate 10 facing downwardly,after the mine has been removed from a minefield, without the firing pin17 having been held by means of the blocking latch 21 via thetimer 23. Adanger also exists that a faulty timer 23 has released the firing pin 17within fractions of a second instead of in 1 or 2 minutes and thelandmine falls or is dropped onto the ground with its pressure plate 10facing downwardly. If this should happen from a relatively high height,e.g., more than 100 cm, the plunger 4 will be momentarily pushed inrelatively rapidly via the pressure plate 10, against the force of thespring 5, after the spring force of the resilient ring 36 has beenovercome, but the inertial resistance to movement of the flyweight 30 inthe housing 1 will retain the flyweight in position in the housing sothat the plunger 4 will move relative to the flyweight 30 and the firingpin 17 will be held safely in its rearward position by the firing lip34. If an accidental fall of low height, e.g., less than 100 cm, theelastic ring 36 prevents the plunger 4 from being pressed into thehousing 1 by the pressure plate 10 which would happen in the absence ofthe ring 36, so that the landmine is not detonated.

When a vehicle drives over the top of the landmine, the plunger 4 isforced downwardly againt the force of the spring 5 at a slower rate thanwhen the landmine is dropped. In this case the flyweight 30 is forceddownwardly by the spring 31 at the same rate as the plunger 4 to thuslower the firing lip 34 thereby enabling the firing pin to hit theinitial triggering device 27 and detonate the landmine.

It is noted that the plunger 4 is circular in crosssection over itsentire height except for the recess 29 andthat the flyweight 30 and therecess 29, when taken together with the plunger 4, are circular incrosssection. The opening in the guide 3 that receives the plunger 4 andthe flyweight 30 is also circular in crosssection. This constructionprovides the advantage that the triggering mechanism in the center ofthe landmine can be made relatively small which enhances the explosiveeffect of the landmine. This construction also simplifies themanufacture of the landmine.

thetic material by injection-molding without adversely affecting theoperation of the triggering mechanism.

As noted above, the flyweight 31 is made of a high density material suchas non-rusting steel while the plunger 4 and the guide 3 are preferablymade of a synthetic plastic. This enables the flyweight, plunger andguide to be made relatively small to produce an improved explosiveeffect for the landmine without the flyweight leaving too small a mass.In addition, this enables malfunctions caused by corrosion to beeliminated.

From the foregoing it can be seen that a landmine according to theinvention which has been dropped from a truck, for example, and whichhas previously been armed will not be triggered because when the minelands with the pressure plate 10 down, the plunger 4 can be pressed intothe mine housing 1, against the spring force of the plunger spring 5,but at the same time the flyweight 30, which blocks the firing pin 17,moves relative to the plunger and in a direction opposite theretobecause of its inertial resistance to movement so that the flyweightdoes not change its position with respect to the firing pinv and thuscontinues to arrest it.

The same effect occurs when the landmine is picked up for purposes ofcamouflage and is inadvertently dropped. If the landmine is howevertravelled over by a vehicle where the plunger 4 is depressed into thehousing substantially slower than after a free fall, the

flyweight 30 is not prevented by its inertial resistance to movementfrom moving with the plunger, but is rather displaced by the springelement 31 disposed be-.

tween the plunger and the flyweight in the same direction with theplunger and releases the firing pin 17.

If, however, the mine, when it is dropped, falls bottom-down, thelandmine will also not be triggered because the spring force' of theplunger spring 5 applies a greater upward force than the downwardinertial force that would be applied by the plunger 4 and the flyweight30.

With lesser dropping heights, e.g., less than 100 cm, theabove-described flyweight safety which was selected to be relativelysmall to obtain the optimum explosive effect, cannot become effectivebecause with lower dropping heights the inertia of the flyweight 30 issuch that it does not move in a direction opposite to the plunger sothat the firing pin 17 would be released. In order to make the mine safealso for these low dropping heights, the elastically yielding resilientring 36 prevents the plunger 4-from moving when the landmine fallsbottom-down. However, the ring 36 is compressed sufficiently to enablethe plunger to move down when it is being driven over so that a perfecttriggering of the landmine can occur via the pressure plate 10 and theplunger 4. To further increase the safety when dropping a landmine, thelandmine includes the timer 23 which blocks the firing pin 17 and whichruns down and releases the firing pin after its handle 26 has beenrotated by This results in the further advantage that the abovedescribedlandmine can now be dropped from a greater height than before althoughthe flyweight safety assures non-triggering of the landmine, if thelandmine lands bottomdown, only up to a certain dropping height whichdepends on the mass relationships between the plunger 4, the flyweight30 and the mine housing 1 plus the explosive charge 28 and the othercomponents of the triggering mechanism.

It is important for the faultfree functioning of the above-describedflyweight safety that the stroke of the plunger 4 is limited in thedownward direction by the spacer 9 of thermoplastic synthetic materialwhich is disposed below the plunger and which is supported by theabutment in the form of the screw 8 that is disposed in the mine housing1 and is preferably displaceable, while in the upward direction theplunger movement is limited by the plunger collar 6 bearing against theshoulder 7.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes andadaptations, and the same are intended to be comprehended within themeaning and range of equivalents of the appended claims.

I claim:

1. A landmine comprising, in combination: a housing; a plunger mountedin the housing for heightwise movement; a pressure plate supported bythe plunger; spring means yieldably urging the plunger upwardly to aprescribed position; a flyweight mounted for heightwise movement withrespect to the plunger; a spring element, having less force than thespring means, urging the flyweight downwardly with respect to theplunger to a location that is determined by said prescribed position ofthe plunger; and a spring biased firing pin that bears against theflyweight when the flyweight is in said location and is arranged to bereleased from the flyweight when the flyweight moves downwardly of saidlocation; whereby when the plunger is forced downwardly of saidprescribed position at a relatively slow speed the flyweight will movedownwardly with the plunger to release the firing pin and when theplunger is momentarily forced downwardly of said prescribed position ata relatively high speed the inertial resistance to movement of theflyweight will retain the flyweight in said location so that the firingpin will not be released.

2. The landmine as defined in claim 1 further comprising: means mountingthe flyweight for heightwise movement in the plunger.

3. The landmine as defined in claim 2 further comprising: a recess inthe plunger, in which the flyweight is mounted for said heightwisemovement, in that side of the plunger which faces the firing pin; boresin the plunger and the flyweight having greater crosssectional areasthan that of the firing pin located in alignment with the firing pin;and a firing lip in the bottom of the flyweight bore that bears againstthe front of the firing pin when the flyweight is in said location;

and wherein said spring element is a compression spring disposed in therecess between the flyweight and the plunger.

4. The landmine as defined in claim 2 further comprising: a recess inthe plunger in which the flyweight is mounted for said heightwisemovement; and an open ing in the housing that receives the plunger forsaid heightwise movement; and wherein: that portion of the plunger thatdoes not include the recess is circular in cross-section; that portionof the plunger that contains the recess, when taken together with therecess and the flyweight, is circular in cross-section; and said housingopening has a cross-section complementary to the first mentioned crosssections.

5. The landmine as defined in claim 1 further comprising: a spacer,located below the plunger, for determining the limit of downwardmovement of the plunger; a guide in the housing in which the plunger ismounted for said heightwise movement; a downwardly facing shoulder onthe guide; and a. collar in the plunger that abuts the shoulder todetermine said prescribed position of the plunger.

6. The landmine as defined in claim 2 further comprising: a recess inthe plunger, in which the flyweight is mounted for said heightwisemovement; and opening in the housing that receives the plunger for saidheight wise movement; and wherein the cross-sections of theplunger-flyweight-recess assembly and of the housing opening diminish asthey progress upwardly toward the pressure plate.

7. The landmine as defined in claim 1 wherein the flyweight consists ofa heavy high density material.

8. The landmine as defined in claim 1 further comprising: a resilientring secured to the housing and extending above the top of the pressureplate, whereby if a pressure less than a predetermined amount is appliedto the top of the landmine the ring will compress without forcing theplunger downwardly an amount sufficient to release the firing pin.

9. The landmine as defined in claim 1 further comprising: a timer; ahandle mounted to the timer for movement between a first position and asecond position; and means so connecting the timer to the firing pin asto cause the timer to restrain the firing pin against movement when thehandle is in said first position and to cause the timer to release thefiring pin for movement a preselected time after the handle has beenmoved to said second position.

10. The landmine as defined in claim 1 further comprising: a spacer,located below the plunger, for determining the limit of downwardmovement of the plunger.

11. The landmine as defined in claim 10 wherein said spacer is made of asynthetic material.

* III

1. A landmine comprising, in combination: a housing; a plunger mountedin the housing for heightwise movement; a pressure plate supported bythe plunger; spring means yieldably urging the plunger upwardly to aprescribed position; a flyweight mounted for heightwise movement withrespect to the plunger; a spring element, having less force than thespring means, urging the flyweight downwardly with respect to theplunger to a lOcation that is determined by said prescribed position ofthe plunger; and a spring biased firing pin that bears against theflyweight when the flyweight is in said location and is arranged to bereleased from the flyweight when the flyweight moves downwardly of saidlocation; whereby when the plunger is forced downwardly of saidprescribed position at a relatively slow speed the flyweight will movedownwardly with the plunger to release the firing pin and when theplunger is momentarily forced downwardly of said prescribed position ata relatively high speed the inertial resistance to movement of theflyweight will retain the flyweight in said location so that the firingpin will not be released.
 2. The landmine as defined in claim 1 furthercomprising: means mounting the flyweight for heightwise movement in theplunger.
 3. The landmine as defined in claim 2 further comprising: arecess in the plunger, in which the flyweight is mounted for saidheightwise movement, in that side of the plunger which faces the firingpin; bores in the plunger and the flyweight having greatercross-sectional areas than that of the firing pin located in alignmentwith the firing pin; and a firing lip in the bottom of the flyweightbore that bears against the front of the firing pin when the flyweightis in said location; and wherein said spring element is a compressionspring disposed in the recess between the flyweight and the plunger. 4.The landmine as defined in claim 2 further comprising: a recess in theplunger in which the flyweight is mounted for said heightwise movement;and an opening in the housing that receives the plunger for saidheightwise movement; and wherein: that portion of the plunger that doesnot include the recess is circular in cross-section; that portion of theplunger that contains the recess, when taken together with the recessand the flyweight, is circular in cross-section; and said housingopening has a cross-section complementary to the first mentionedcross-sections.
 5. The landmine as defined in claim 1 furthercomprising: a spacer, located below the plunger, for determining thelimit of downward movement of the plunger; a guide in the housing inwhich the plunger is mounted for said heightwise movement; a downwardlyfacing shoulder on the guide; and a collar in the plunger that abuts theshoulder to determine said prescribed position of the plunger.
 6. Thelandmine as defined in claim 2 further comprising: a recess in theplunger, in which the flyweight is mounted for said heightwise movement;and opening in the housing that receives the plunger for said heightwisemovement; and wherein the cross-sections of the plunger-flyweight-recessassembly and of the housing opening diminish as they progress upwardlytoward the pressure plate.
 7. The landmine as defined in claim 1 whereinthe flyweight consists of a heavy high density material.
 8. The landmineas defined in claim 1 further comprising: a resilient ring secured tothe housing and extending above the top of the pressure plate, wherebyif a pressure less than a predetermined amount is applied to the top ofthe landmine the ring will compress without forcing the plungerdownwardly an amount sufficient to release the firing pin.
 9. Thelandmine as defined in claim 1 further comprising: a timer; a handlemounted to the timer for movement between a first position and a secondposition; and means so connecting the timer to the firing pin as tocause the timer to restrain the firing pin against movement when thehandle is in said first position and to cause the timer to release thefiring pin for movement a preselected time after the handle has beenmoved to said second position.
 10. The landmine as defined in claim 1further comprising: a spacer, located below the plunger, for determiningthe limit of downward movement of the plunger.
 11. The landmine asdefined in claim 10 wherein said spacer is made of a synthetic material.